Method of forming pressed sheet metal spoked wheels



Oct. 22, 1935. I J. MacLENNAN 2,018,078

METHOD OF FORMING PRESSED SHEET vMETAL SPOKED'WHEELS Filed April 1e, 1934 Patented Oct. 22., 1935 UNITED STATES METHOD OF FORMING PRESSED SHEET METAL SPOKED WHEELS John MacLennan, Detroit, Mich., assignor to Kelsey-Hayes Wheel Company, Detroit, Mich., a corporation of Delaware Application April 16, 1934, Serial No. 720,874

5 Claims.

The invention relates to the manufacture of pressed sheet metal spoked vehicle wheels and more particularly that type in which the spokes are of channel cross section having closed outer ends and merg'ing at their inner ends into adished annular portion with a reverse dished or cupped inner portion terminating in a radially inwardly extending bolting-on flange. It is the object of the invention to obtain a method for forming such structure which facilitates the forming of the spokes with their closed ends substantially parallel to the axis of the wheel throughout their extent. It is a further object to fashion the blank without undue localized drawing or thinning of the metal so as to obtain the desired strength in all portions. Still further it is an object to simplify and reduce the number of operations required for completely fashioning the structure. With these objects in view the invention consists in the method as hereinafter set forth.

In the drawing:

Fig. l is a cross section through the sheet metal blank;

Figs. 2 and 3 illustrate the successive steps in cupping the central portion of the blank;

Fig. 4 is a cross section illustrating the operation of simultaneously bowling and corrugating the portion of said blank surrounding said cupped portion;

Fig. 5 is a view similar to Fig. 4 showing the further fashioning of the blank;

Fig. 6 is an elevation of the structure as formed in Fig. 5;

Fig. 7 illustrates the trimming of the perip-hery of the blank;

Fig. 8 is a view similar to Fig. 5 showing the first step in reverse bowling;

Fig. 9 is a similar view showing the final step of reverse bowling;

Fig. 10 is a diagram illustrating in full and dotted lines the successive movements in the reverse bowling of the blank;

Fig. 11 is a plan view of Fig. 9.

Fig. 12 is a cross section through the wheel.

The wheel formed by my improved method is illustrated in Fig. 12 and comprises a cupped center portion A having a radially inwardly extending bolting-on flange B centrally apertured for engaging the wheel hub and provided with the usual bolt apertures C. Surrounding the portion A is a reversely dished portion D and projecting outward from this dished portion are spokes E of inwardly opening channel cross section and which terminate in closed ends F. The ends of (Cl. 29e-159.03)

the spokes llt within the rim G and are secured thereto preferably by rivets H passing through said rim and the closed spoke ends F.

To form this structure from pressed sheet metal and to accomplish the same with a fairly uniform 5 distribution of drawing and compressive stresses I proceed as follows: A circular blank I is centrally cupped by a series of successive operations as indicated at I', I2, Figs. 2 and 3, leaving an outwardlyv extending annular flange I3 in the 10 original plane of the blank. The blank is next pressed between dies J and J which are so fashioned as to bowl the ilange I3, forming thereof a flaring extension K of the cupped portion terminating in a radially outwardly extending and 15 corrugated portion K', the axes of the corrugations being radial with respect to the axis of the bowl as shown in Fig. 5. Following this operation the blank is re-pressed, Fig. 6, to form the top portion K2 of the corrugations in a plane 20 perpendicular to the axis of the bowl and at an angle to the flaring portion of the bowl substantially corresponding to the angle between the dished portion D and ends F of the completed structure. The next operation, Fig. 7, is the 25 trimming of the periphery of the blank or ends of the corrugations The blank is then reverse bowled by successive steps shown in Figs. 8 and 9. In the rst step, Fig. 8, the flange K2 is swung from the planeY transverse to the axis to 30 an angle of substantially 45 thereto as illustrated at K3. In the second step this flange is brought into substantial parallelism to the axis of the bowl as indicated at K4, Fig. 9. The blank as formed in Fig. 9 has the central cupped por- 35 tion, the surrounding reversely dished portion with a series of hollow channel shaped spokes extending radially outward from the dished portion and with closed ends. To complete the structure the completed portion must be pierced 40 and die pressed to form the annular bolting-on flange and to properly fashion the same. These operations are not, however, the subject matter of the present invention and therefore will not 45 be described in detail.

As diagrammatically illustrated in Fig. 10, the

' effect of the operations performed in Figs. 8

and 9 is to swing the corrugated portions of the bowled blank from a radial plane to the periph- 50 ery of the bowl and substantially parallel to the axis thereof. This permits of forming both the ends of the spokes and the spaces between the same by a die operation as shown in Fig. 6, and dispenses with the necessity of cutting out metal 55 between'spokes as has been Vthe usual practiceV in forming spoked wheels. V'Ihl's avoids waste of `metal and results in a stronger structure of more corrugations extending substantially radially and Y at right angles'to the Vaxis of the bowl, and in `reversely bowling the blank thereby bringing said corrugations with their axes substantially parallel to the axis of the bowl and forming a series of spaced radial spokes having closed ends.

2. In a method of forming pressed sheet metal spoked wheels; the steps of cupping the central portion of a flat sheet metalblank', leaving asurrounding annular flange, bowling ,saidvi'lange and thereby forming a ilaringV extension of said Cup with a radially outwardly extending peripheral portion and simultaneously corrugating said peripheral portion with the axes of the corrugations extending radially atsubstantially right anglesto the. axis of thebowl, and in reversely bowling the blank thereby swinging said corrugated portion to the periphery of the bowl with the axes of the corrugations substantially parallel to the axis of the bowl.

3. In a method of forming pressed sheet metal spoked wheels, the steps of cupping the central portion of a flat sheet metal blank leaving a surrounding annular flange in the original plane, bowling said flange and thereby forming a ar ing end to said cupped portion, corrugating a portion of said ilaring portion to initiate spokes therein, and reversely bowling thereby bringing said spokes into a substantially radial plane.

4. In 'a method of forming pressed sheet metal spoked wheels, the stepsof cupping the central portion of a at sheet metal blank leaving a surrounding annular flange` in the original'plane, bowling said flange and thereby forming a flaring extension of said cup, pressing pockets inward from the convex side of said bowl thereby forming projections from thev concave side thereof and reversely bowling thereby bringing said projections into a substantially radial plane.

5. In a method of forming pressed sheet metal spoked wheels, the steps of cupping the central portion of a at sheet metal blank leaving a sur-VV rounding annular flange in the original plane, bowling said flange and thereby forming a ilaring extension of said cup, pressing pockets in said bowl from the convex side thereof thereby forming projections from the concave side, reversely bowling thereby bringing said projections on to the convex side thereof, with their outer ends closed.

JOHN MACLENNAN. 

